Bit block for cutter chains



,1940. v E. P. STENGER ET AL ,00 0

BIT BLOCK FOR CUTTER CHAINS Fi led May 7, 19:55

lNvExTORs Patented Feb; l3, rate BIT BLocK roa cum-En CHAINS Edwin P. Stenger and Armin OQ-Bruestle, Cincinnati, Ohio, assignors to The Cincinnati Mine Machinery Company, Cincinnati, Ohio, a corporation of Ohio Application May 'i, 1935, Serial No. 20,227} 4 1 Claim. I

This invention relates to mining machinery and is particularly directed to improvements in mining machine chain, specifically the. holders incorporated in the chain links or blocksfor mounting cutter bits or teeth. Endless chains are employed carrying cutter teeth or bits in the respective chain blocks. These bits are angularly laterally disposed and forwardly projected for making a cut through coal. The angle of mounting of the teeth is varied in transverse planes, Whereby the successive teeth make a out which is of sufficient width to permit easy passage of the run of chain and the cutter bar through the cut. Inasmuch as the present invention is primarily directed to the construction of the holders incor-'v pcrated in a chain, it is only necessary for the purpose of clearly describing and illustrating the same that reference be made to one block'or link of the cutter chain.

The average cutter tooth or bit is subjected to extremely damaging usage and it is constantly necessary to replace the bits. Accordingly, it is an object of the present invention to provide an dill improved bit holder means incorporated in the chain block or box which is conveniently and quickly manipulated by the operator for removing the worn bit and inserting a new bit, or, reversing the worn bit end for end in cases where a revers- 'lble bit is used, thereby reducing bit setting time to a minimum. The ability-to quickly set the bit is a distinct time saving advantage since the average miner is required to set hundreds of bits per day. I Because of the varying character of material through which the bits are drawn for the purpose of making a cut, a great many bits are lost. This occurs because of chattering or vibration resulting from pounding, or may occur due to the fact that the bits are sprung from position due to the excessive pressure which develops as they are forced against materials of great hardness. It is accordingly a further object of the invention to provide an improved bit or tooth mounting as embodied in the structureof the'holder or box which is of improved holding efficiency. This appreciably lowers the amount of loss of bits from coal cutting chains, thereby resulting in a great saving or economy in the operation of the mining machine.

Due to the excessively hard usage to which the bits are subjected, it is of course highly essential that the construction of the holder as incorporated in the chain link or box be extremely rugged and durable so that breakage rarely occurs. Therefore it is a still further object of this in- In order to accomplish eflicient coal cutting, it

is also necessary that the bit have. ample clearance or projection beyond the line of the lug or box and the holder means as incorporated therein. 10 It is accordingly a further object of this inventionto provide a bit holder or'mounting inlthe box or block, which, because of the durability 'ofthe holder and the manner in which the forces acting on the bit are absorbed within the holder, permits 5 ample extension of the cutting point of thefbit without overloading the structure of the holder means or the box. Therefore it does not split or deform, breakage and distortion of the parts being reduced to a minimum. This structure or ar- 0 rangement resultsin a good ratio betweenflbit clearance and the lengthof the bit whichis one ,;of thefeatures constantly sought after inthis type of apparatus sinceit has a very important thereof. i Other objects and further advantages will be more fully apparent from a descriptionotf the accompanying drawing, in which: V

Figure 1' is a side view of" a length of mining 30 machine chain, incorporating the improved cutter tooth mounting.

Figure 2 is a top plan view of a section of the chain, illustrating a lug of the chain ,run incorporating the present improvement. 5

Figure 3 is a sectional view taken onlirieS-S, Fi r a Figure 4 is a sectional view taken online 4- 4, Fig. 1, with the bit removed. Figure 5 is a sectional view taken on line ,55. 4 Fig. 2, illustrating the internal construction of the lug andshowing thebit held in position.

Figure 6 isa view taken similar to Fig. 5, but

showing the holder means adjusted for removal of the bit. In view of the fact that the present improvements relate only to the structure for mounting the bit as incorporated in one of the chain. lugs,

erence to the drawing, the alternately disposed links, commonly known as boxes or blocks, will be found at 10 and the connecting links of the 5 7 chain at H, the elements In and II of the chain inclined at substantially the same angle as the socket. iary lug portion I8 is provided for receiving a Forward of the heavier bit lug an auxilclamping screw it.

The bit 20 adapted for mounting in this holder socket is of diamond shaped crosssection and has obliquely cut end surfaces appearing from the same side of the bit, these obliquely out ends approaching each other at a longitudinal side edge of the bit and accordingly providing sharp points 2] at the opposite longitudinal side edge thereof. cross section to receive the bit 20.

A clamping arm or lever 22 is pivoted .on a cross pin 23 extended between the side plates l5, l5, below the space between the two lugs l3 and IS. The pivot pin of the clamping arm therefore is located below the clamping screw IS. The forward surface 24 of the clamping arm or lever is engaged by the rounded contact end of the clamping screw.

Accordingly, operation of the screw in the proper direction swings the clamping arm toward the bit lying against the opposite wall of the socket. The bit is supported and limited in its inward movement by means of a cross pin 25 disposed in the lug transversely through the socket- The pin is flattened for increased contact with the oblique end face of the bit.

The upper or bit engaging face of the clamping arm is grooved as at '26, the flat bottom of the groove engaging the end face of the bit at the lower end thereof.

Now one of the decided advantages of this construction is that it requires only a fraction of a turn ofthe clamping. screw to completely clear the clamping arm for removal of the bit. Inasmuch as these bits wear out very rapidly and considerable breakage may occur due to the fact that a rock s'trata is encountered, it is highly important that the operator be able to remove the bits with great rapidity. Also, it is of primary,

importance that he be able to manipulate the parts in a dark mine without difficulty and that it be impossible for him to lose any of the holder parts. Therefore, it is desirable to arrange the parts so that they do not become displaced entirely from the chain. Obviously since the clamping arm is pivoted it is a permanently fixed part of the chain lug and the only removable part in the present construction is the bit itself.

The socket I4 is diamond shaped in The accomplishment of easy and quick extraction is the result of a careful selection of the angular relation of the clamping arm relative to the set screw so that the pivotal movement tends to clear the end lug very rapidly and upon very little movement.

In order to provide great durability, the mass of the holder lug must be properly distributed. In the present mounting of the bit it has been provided that the heavy pressure exerted on the bit as it is cutting is active against the heavy mass of metal in back of the bit and is not in any way borne by the clamping arm. Moreover,

there is no tendency for the bit to become outwardly displaced since the pressure tends to force it into the socket at all times.

In the distribution of the mass of the holder lug it must be remembered that adequate bit clearance is necessary for efllicent use of the bits. In other words, the projection of the bit beyond the extreme outer end of the clamping arm and the lug must be substantial. Accordingly, the clamping arm or lever has been made relatively short and only extends a short distance-in contact with the outer oblique end face of the bit. This leaves practically the entire cutting edge as represented by the side edges of the oblique forward face clearfor cutting (see Figure 5). As stated this contact is suflicient since the greater percentage of the work thrust on the bit is carried by the holder lug. I

A coil spring 42 under compression is provided, surrounding the screw, between the clamping plate 35 and the lug so as to press the clamping plate away from the bit when the adjusting screw is turned for releasing the bit.

Due to the angular relationship of the bit end surface and the engaging surface of the clamping arm relative to the longitudinal axis of the bit or hit socket and the relationship of the pivoted lower edge of the clamping surface, it is provided that very little turning of the screwis necessary to fully release the bit. At the same time the bit is firmly clamped in position for cutting operations under the most unfavorable working conditions.

Having described our invention, we claim:

In a mining machine chain, a link including a lug portion, said lug portion having a bit receiving bore extending completely therethrough, and an abutment within said bore forming an inclined rear wall, a bit positioned within said bit bore, said bit being trapezoidal in side elevation and having cutting points at the opposite ends thereof, a clamping arm pivotally mounted in the link and having its swinging end outwardly disposed and adapted to engage against the active cutting'surface of the bit to obstruct outward movement of the bit and means for moving the arm towards the inclined rear wall.

I EDWIN P. STENGER.

ARMIII' O. BRUES'I'LE. 

